STROKE INCIDENCE AND MORTALITY CORRELATED TO STROKE RISK-FACTORS IN THE WHO MONICA PROJECT - AN ECOLOGICAL STUDY OF 18 POPULATIONS

Background The aim of the present study was to determine the extent to which the variation in conventional risk factors contributed to the v ariation in stroke incidence among these populations. Methods Within t he WHO MONICA Project, stroke has been recorded in 18 populations in 1 1 countries. In population surveys, risk factors for cardiovascular di seases have been examined in the age group 35 to 64 years. Over a 3-ye ar period, 12 224 acute strokes were registered in men and women withi n the same age range. Results The highest stroke attack rates were fou nd in Novosibirsk in Siberia, Russia, and Finland, with a more than th ree-fold higher incidence than in Friuli, Italy. The mean diastolic bl ood pressure among the populations differed by 15 mm Hg between Novosi birsk (highest) and Denmark (lowest). In multiple regression analyses, the presence of conventional cardiovascular risk factors (smoking and elevated blood pressure) explained 21% of the variation in stroke inc idence among the population in men and 42% in women. In Finland, in Ch ina, and in men in Lithuania, the stroke incidence rates were higher t han expected from the population risk factor levels. Conclusion Preval ence of smoking and elevated blood pressure explain a substantial prop ortion of the variation of stroke attack rates between populations. Ho wever, other risk factors for stroke that were not measured in the pre sent study also contribute considerably to interpopulation differences in stroke rates.